1. Field of the Invention.
The field of the invention is broadheads or points (also called arrowheads) for arrow shafts used with a bow for hunting. More particularly, the field involved concerns broadheads which assume one configuration during flight and a second configuration after it strikes the target, such as to more efficiently accomplish its function of humanely disabling and killing the game animal.
2. Description of the Related Art.
In recent years there has been significant advances in the art of broadheads for hunting arrows designed to cause the animal to cease its travel by more effectively disabling and killing the animal being hunted and while doing so, reduce suffering by the animal.
Other inventions include the arrowhead assembly by Vance in U.S. Pat. No. 2,820,634 where two blades pivotably mounted to the head of the arrow shaft, when striking the side of the animal, immediately begin to rotate past each other to a expanded "V" configuration. The blades are initially joined in a somewhat pointed orientation. It is noted that the sharpened edge which is presented in the initial orientation remains the sharpened edge in the final opened "V" configuration.
The patent of Vance is modified somewhat in Rickey, U.S. Pat. No. 3,578,328, where in a similar construction, the arrow shaft body continues beyond the front point of the two pivotable blades to form a front piercing point. The two blades, like those in Vance, rotate past each other when rotational movement is forced upon the blades by the blades engaging the hide of the animal. A same sharpened edge which engages the animal initially is the forward sharpened edge as the arrowhead proceeds through the body of the game animal.
Lastly, Steinbacher in U.S. Pat. No. 2,568,417 adopts the forward point of an arrow shaft as the leading point and secures rotatable blades within the arrow shaft forward point. The blades are rotated outwardly not crossing each other as outstanding flanges on the blades engage the animal after initial penetration by the forward point portion. Other U.S. patents which show features similar to the features described above but constructed in a different manner include Bergmann, U.S. Pat. Nos. 4,166,619; Vocal, 4,615,529; Cox, 3,738,657; and Hendricks, 3,600,835.
All of the above prior art patents are characterized by arrowpoint bodies which have protruding spurs or cutting blades extending outwardly from its sides, some extending prior to the arrowpoint entering the body of the animal and some extending after the arrowpoint has entered the body of the animal. The extending blades or spurs appear to accomplish their function very efficiently, i.e., that of cutting as wide a swath as possible in order to bring the game down.
All of the arrowheads or points illustrated above employ a cylindrical pointed arrowhead body (with the exception of Vocal and Vance) with the spurs or blades emerging from the body, either being pivotable near the head of the body or at the rear of the body, some pivoting upon entering the body of the animal and some pivoting after entry into the body of the animal. This, of course, is not without reason since for the arrow to travel through to its target with minimum air resistance, it is generally necessary that the smallest point cross-section as possible be utilized. However, the cylindrical body portion of the arrow point itself is relatively inefficient as it contributes very little to the end results of the arrowhead.
Thus, the relative efficiency of the arrowhead or point may well be improved if the whole point itself comprises the blades which ultimately rotate outwardly. Vance does present an arrowhead assembly wherein the cutting blades also comprise the forward point, however, the blades are so arranged that they commence rotation and open to the widest possible configuration immediately upon hitting the hide of the animal and thus suffer the possibility of not only dulling on the animal hide, especially if the animal has dried mud or dirt on its side, which is highly likely, but also being forced to engage a heavy hide in the open position on initial penetration and thereby wasting considerable energy. In addition, since the sharpened edges are always exposed, a safety hazard is always presented to the hunter in handling the arrowhead prior to use.
It is also apparent that an obvious improvement to the state of the art exists if the rather small point on the arrow shaft necessary for guiding the arrow to it's mark should, upon striking the animal, metamorphosis entirely into outstanding cutting blades which bring down the game more efficiently.
It is also apparent that an obvious improvement exists if the sharpened edges can be protected against dulling or operator injury prior to the arrowhead entering the body of the game animal. Further it would also be a considerable improvement if both blades could be locked together during initial penetration until the heavy hide and ribs have been penetrated.